PEMBERTON TOWNSHIP, N.J. -- Officials believe off-road vehicle riders in New Jersey's Pinelands ripped up 400 trees days after they were planted by teenagers.

Jason Howell of the Pinelands Preservation Alliance tells NJ.com he returned to the site to install barriers at the Bucks Cove Run Preserve in Pemberton Township and found the site "completely torn up" and a trash fire still smoldering. Off-road vehicle tracks were on the ground.

The state Environmental Protection Department says it is aware of the vandalism and park police at nearby Brendan T. Byrne State Forest are increasing enforcement.

Off-road vehicles are prohibited on Pinelands land managed by nonprofits and the state. However, licensed and registered vehicles can be driven on roadways.